$(document).ready(function() {
	$('#draggable, #target_draggable').draggable();
	$('#droppable').droppable({
		hoverClass : 'hover',
		accept : $('#target_draggable'), //accept으로 지정한 객체에만 drop 반응.
		drop : function() {
			$(this).addClass('drop').text('Drop Success');
		}
	});
});